[Builder] Display Lowest Price Source

{"ops":[{"insert":"I have considered adding something like what you're asking for specifically to the buy modal before. But the reason that I haven't is because not all price sources have a bulk export option. So if one was the cheapest, but that didn't have a bulk export link (like opening a vendor with multiple cards at once) it becomes a bit problematic. \n\nI don't hate this idea. My first concern is mostly that we'd need to denote which currency every vendor uses. Since not all vendors are in USD, we obvioulsy wouldn't want to compare those. This also kinda rasies the issue that this only helps users using USD since that's the only currency we support multiple vendors for. \n\nI'll give this some thought. It's a good idea, but might take some fiddling.\n"}]}